LocalTalk and PhoneNet

The original Apple LocalTalk wiring scheme required special cables, available from Apple in certain lengths, but rather expensive. It was easy to set up, did not use a terminator, but was limited to 8 devices.

Farallon PhoneNet added the ability to connect many more devices and much more wire. The wiring is really cheap, no special cables required, but it asks that you plug a terminator into the last empty socket at each end of the chain. With PhoneNet, you can connect up to 32 devices on that LocalTalk network, and the wiring length limit is typically in excess of 1800 feet.

If you are using a Farallon EtherMac iPrint LT, the end that plugs into the iPrint protocol converter needs neither a PhoneNet box nor a terminator -- it offers a single telephone jack for a lead-in cord.

But let us suppose you had PhoneNet boxes galore but NO terminating resistors.

PhoneNet wiring uses the outer two wires in a four wire telephone cord. That is why your phone cords MUST have all four wires. The inner two are most often the red and green regular telephone talk pair, and are avoided. This means you can also use the spare pair in the telephone wiring in your house to send PhoneNet all over the house.

There are detailed instructions for this wiring in the manuals that shipped with new PhoneNet boxes. They also note that if you have a long PhoneNet run that ends at a wall jack that is infrequently used, you can simply wire the terminating resistor into that jack, and not add a phoneJack resistor at the PhoneNet box at that location.

The required resistor is a 120 Ohm resistor (they suggest a fairly precise one if possible, with a gold band). Any wattage is okay. The resistor can be added to a telephone wall jack, or a spare modular jack, and is placed across the yellow and black (outer) leads.

In summary: No terminating resistor? Buy a 120 Ohm resistor and wire it across the yellow and black leads in a wall mount modular jack. Plug an additional four wire phone cord from the last open jack on the last PhoneNet connector to your wall jack, and that end of the network is terminated.

You also asked where to get more phonejack-mounted terminating resistors. The best source is the same used-computer outlets that can sell you more PhoneNet connectors. In the US, eBay is also a good source -- just look through the listings for PhoneNet jacks until you find someone offering the resistors, too.

If you have access to the crimping tool for making Ethernet cables or telephone cables, you can usually use the same crimping tool to crimp your own 120 Ohm precision resistors into the outer positions of a regular RJ-11 four wire phone jack. Unfortunately, this is one job pliers alone cannot do.